Synthesis and photoluminescence characteristics of high color purity Ba3Y4O9:Eu3+ red-emitting phosphors with excellent thermal stability for warm W-LED application

摘要

Single phase Eu ~(3+) -activated Ba _(3) Y _(4) O _(9) (Ba _(3) (Y _(1? x ) Eu _( x ) ) _(4) O _(9) ) red-emitting phosphors with different Eu ~(3+) doping concentrations were synthesized by a high temperature solid-state reaction method. The phase purity, crystal structure, photoluminescence properties, internal quantum efficiency, decay lifetimes, and thermal stability were investigated. Upon excitation at 396 nm near-ultraviolet light and 469 nm blue light, the Ba _(3) (Y _(1? x ) Eu _( x ) ) _(4) O _(9) phosphors exhibited a strong red emission at 614 nm due to the ~(5) D _(0) → ~(7) F _(2) transition of Eu ~(3+) ions. The optimal doping concentration of Eu ~(3+) ions in Ba _(3) (Y _(1? x ) Eu _( x ) ) _(4) O _(9) was found to be x = 0.25. Furthermore, the critical distance was calculated to be 12.78 ? and the energy transfer mechanism for the concentration quenching effect was determined to be quadrupole–quadrupole interaction. In addition, the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates of Ba _(3) (Y _(0.75) Eu _(0.25) ) _(4) O _(9) phosphors were measured to be (0.6695, 0.3302) which located at the red region, and significantly, the high color purity was about 97.9%. The as-synthesized phosphors also possessed excellent thermal stability and the activation energy was determined to be 0.29 eV. Therefore, the investigated results indicated that the Ba _(3) Y _(4) O _(9) :Eu ~(3+) phosphor may be a suitable candidate as a red phosphor for white light-emitting diodes under effective excitation at near-ultraviolet and blue light.